Maglite flashlights are known around the world as a brute force, get-the-job-done, heavy duty flashlight. As with all flashlights, they require batteries. Sometimes, it may be years between battery changes on a Maglite flashlight which could result in unseen battery leakage occuring inside the body of the flashlight and subsequent corrosion due to the acid released from the batteries.

Although Maglite has a lifetime warranty in the US and Japan and a 10 year warranty elsewhere, they will not warrant against defective batteries. If you send your flashlight to Maglite, looking for warranty service, with corroded batteries stuck inside the light, they will destroy the batteries when they remove them from the light, thus destroying any evidence you have in a claim against the manufacturer of the batteries.

If you have a Maglite with batteries corroded and stuck inside the body of the light, the only way to make any sort of claim is to send the light to the company that manufactures the batteries. So, you will need to know what type of batteries are inside your flashlight.

The instructions that are packaged with all Maglite flashlights reads as follows regarding battery leakage:

If the flashlight has been damaged by leakage of batteries, do not return the flashlight to Mag but determine what brand of battery caused the damage and follow the battery manufacturer’s instructions about how to make a damage claim.

There are several ways that you can prevent this sort of corrosion damage to your Maglite. Some of them are:

- Only use high quality batteries such as Duracell, Energizer, Eveready, etc in your Maglite Flashlight - Do not mix and match batteries. If one is a Duracell, they should all be Duracell. - Peridically (a couple of times per year) open the tail cap on your Maglite to inspect the battery compartment for evidence of battery leakage.

Upon inspection, if any corrosion is found, I would suggest taking the light apart (remove the head, tail cap, batteries and switch assembly) and neutralizing the acid inside the body of the flashlight with baking soda, then clean it out really good with clean water. Let it dry and reassemble with fresh, new batteries. If the switch assembly or other parts have been damaged by the corrosion, you can get parts for your Maglite at http://maglitesales.com/maglitestore

Here's an update to this thread with information directly from the Maglite website Frequently Asked Questions.

I can’t remove the tailcap from my Mag® flashlight. I have even put pliers on it and tried to twist it off, but it's absolutely frozen or stuck. Is this problem covered by my warranty?When you cannot remove the tailcap to change the batteries, it almost certainly indicates that the batteries have leaked and sealed everything inside the flashlight. Unfortunately, Mag does not warrant against battery leakage, however, we do have agreements with Duracell, Eveready and Ray-O-Vac. If one of these brands of batteries has leaked in your flashlight, send the flashlight to us and we will repair or replace it at no charge to you. We recommend that you ship the flashlight UPS or Postal Insured for tracking purposes. Please send to:Mag Instrument, Inc.Attn: Warranty Dept.1721 E. Locust St.Ontario, Ca. 91761-7769

You pay the freight to us and we pay it going back. Please also include a letter with your name, address, phone number and description of the problem. Don’t forget to indicate what brand of battery is inside if you know. Once we verify it is Duracell, Eveready or Ray-O-Vac, we will send you a new flashlight at no charge. Occasionally we open the flashlight and we find it contains leaking batteries that are not Duracell, Eveready and Ray-O-Vac. In cases of "off-brand" battery leakage, we can replace your flashlight for a charge of -- $12.00 plus your state's sales tax for a ‘C’ or ‘D’ Mag-Lite® flashlight, or $8.00 plus tax for a Mini-Maglite® flashlight. If you are not sure, send the flashlight to us, with the batteries inside, and we will check to determine the brand. If we find that they are "off-brand" batteries, we will contact you and arrange for payment before sending you the replacement flashlight.------------------------------------------------------------------------------------I can’t get the batteries out of my flashlight. They're stuck inside. How do I change them? Is this covered by my warranty?When this happens, it almost certainly means that the batteries have leaked and are stuck inside the barrel. Note: Batteries normally swell before leaking causing them to get stuck inside the barrel. Mag Instrument does not warrant against battery leakage, however, we do have agreements with Duracell, Eveready and Ray-O-Vac that allow us to replace your flashlight. If one of these brands of batteries is stuck (by leaking in your flashlight), send the flashlight to us and we will repair or replace the entire flashlight at no charge to you. We recommend that you ship the flashlight UPS or Postal Insured for tracking purposes. Please send to:Mag Instrument, Inc.Attn: Warranty Dept.1721 E. Locust St.Ontario, Ca. 91761-7769

You pay the freight to us and we pay it going back. Please also include a letter with your name, address, phone number and a description of the problem. Don’t forget to indicate what brand of batteries is inside if you know. We will check to verify that it is Duracell, Eveready and Ray-O-Vac; and if it is, we will send you a new flashlight at no charge. Occasionally we open the flashlight and we find it contains leaking batteries that are not Duracell, Eveready and Ray-O-Vac. In cases of "off-brand" battery leakage, we can replace your flashlight for a charge of -- $12.00 plus your state's sales tax for a ‘C’ or ‘D’ Mag-Lite® flashlight, or $8.00 plus tax for a Mini-Maglite® flashlight. If you are not sure, send the flashlight to us, with the batteries inside, and we will check to determine the brand. If we find that they are "off-brand" batteries, we will contact you and arrange for payment before sending you the replacement flashlight.

I maintain a sailing yacht and have tried all types of flash-lites. Corrosion seems to affect the AA maglite especially. They need to line the flash-lite barrel with a thin sheet of insulation. Once the anodized interior finish is scratched or corroded it's history for the maglite. The "Streamlite JR Luxeon" seems to out perform everything in the AA class. I carry the Streamlite JR all day in this salt water environment and it has never let me down.

Three of the Mini Mag flashlights I’ve owned have been rendered useless due to corrosion/expansion of the batteries, twice with Energizer batteries and once with Duracell batteries. In all three incidents, the batteries had been in the flashlights for less than a year; in one case the batteries had been in the flashlight for less than four months. I have owned several other brands of the smaller AA battery powered flashlights, none of which have given me any problems with battery corrosion.

One thing I’ve noticed is that the batteries only seem to corrode in Mini Mags that are seldom used (i.e., one that’s stored in the glove compartment of a vehicle). When I was doing building maintenance I had a mini mag that I carried in my tool belt that I used on a daily basis and I never had any battery corrosion problems with it.

As far as the cause of the battery corrosion, one theory I’ve heard is that there’s a trickle current that occurs when a Mini Mag is allowed to sit unused and this causes the batteries to slowly drain, resulting in swelling and corrosion. This possibly ties in with the previous posters suggestion of the need for a lining in the barrel of the flashlight as a means of insulation.

I have a 6 cell mag with an LED bulb after less than 6 months my rayovac batteries leaked and the battery swelled up and when i try to take the switch out the 2 MM and 5/64 allen wrenches will not work and i use the flashlight every night taking my dogs out so i can watch for the bears>

top69cat69 wrote:I have a 6 cell mag with an LED bulb after less than 6 months my rayovac batteries leaked and the battery swelled up and when i try to take the switch out the 2 MM and 5/64 allen wrenches will not work and i use the flashlight every night taking my dogs out so i can watch for the bears>

The set screw in the LED lights uses a Torx bit, not an allen wrench. I don't know the size off the top of my head.